In order to achieve better network performance, a self-optimized network is necessary. For example, a load balance feature for the self-optimized network needs resource status exchange between eNBs (eNodeBs).
In current X2AP (Application Protocol) specifications in 3GPP TS36.423: “Evolved Universal Terrestrial Radio Access Network (E-UTRAN); X2 application protocol (X2AP)”, a Resource Status Reporting Initiation procedure is introduced for resource status exchange between different eNBs through X2 interface, and may be used by one of the eNBs to request reporting of load measurements to another eNB. That is, it is possible to setup a measurement report of certain information on a per cell basis by means of the Resource Status Reporting Initiation procedure.
In particular, the following types of load measurements information can be set for periodic updating:                PRB Utilisation        TNL load Indication        HW (Hardware) Load Indication        Composite Available Capacity        ABS (Almost Blank Subframe) Status        
A request message, e.g. a RESOURCE STASTUS REQUEST message, may be used in the Resource Status Reporting Initiation procedure for both starting and stopping the measurement report of the above information.
As per the X2: RESOURCE STATUS REQUEST message tabular in Table 1 that is taken from TS36.423, in order to start a measurement reporting procedure, a Registration Request IE (Information Element) shall be set in the RESOURCE STASTUS REQUEST message to a value “start”, while a list of types of load measurements information to be periodically reported shall be outlined via a bit string in the Report Characteristics IE and a list of cells for which resource status reporting needs to be started shall be specified in a Cell To Report Item IE.
TABLE 1RESOURCE STATUS REQUEST message defined in Section 9.1.2.11 of TS 36.423IE type andAssignedIE/Group NamePresenceRangereferenceSemantics descriptionCriticalityCriticalityMessage TypeM9.2.13YESrejecteNB1 MeasurementMINTEGERAllocated by eNB1YESrejectID(1 . . . 4095, . . .)eNB2 MeasurementC-ifRegistrationRequestStopINTEGERAllocated by eNB2YESignoreID(1 . . . 4095, . . .)RegistrationMENUMERATEDA value set to “stop”,YESrejectRequest(start, stop, . . .)indicates a request tostop all cellsmeasurements.ReportOBITSTRINGEach position in theYESrejectCharacteristics(SIZE(32))bitmap indicatesmeasurement object theeNB2 is requested toreport.First Bit = PRB Periodic,Second Bit = TNL loadInd Periodic,Third Bit = HW Load IndPeriodic,Fourth Bit = CompositeAvailable CapacityPeriodic, this bit shouldbe set to 1 if at least oneof the First, Second orThird bits is set to 1,Fifth Bit = ABS StatusPeriodic.Other bits shall beignored by the eNB2.Cell To Report1Cell ID list for whichYESignoremeasurement is needed>Cell To Report1 . . .EACHignoreItem<maxCellineNB>>>Cell IDMECGI——9.2.14ReportingOENUMERATEDYESignorePeriodicity(1000 ms, 2000 ms,5000 ms, 10000 ms, . . .)Partial SuccessOENUMERATEDIncluded if partialYESignoreIndicator(partial successsuccess is allowedallowed, . . .)
In order to start reporting measurement of different information at different times and/or for different cells, separate RESOURCE STSTUS REQUEST messages may be sent to a neighboring eNB.
However, in order to stop reporting of such load measurement information, the following mechanism is specified in the current TS36.423:
The stop procedure is initiated with the RESOURCE STATUS REQUEST message sent from a requesting eNB (called eNB1) to a receiving eNB (called eNB2, for it is requested to report the load measurements, it is also called reporting eNB). Upon receipt, the eNB2 shall stop all cells measurements which have been started previously and terminate the reporting, when the received Registration Request IE indicates “stop”.
It should be noted that in the current TS 36.423, the Cell To Report IE is mandatory in the RESOURCE STATUS REQUEST message, even if the Registration Request IE is set to “stop”. What's more, the minimum value of Cell To Report Item which is included in Cell To Report IE is 1 (see “1 . . . <maxCellineNB>” in Table 1) which indicates at least one cell ID should also be included in Cell To Report IE. In case that the eNB2 receives the Registration Request IE set to “stop”, the list of cells included in Cell To Report IE is ignored by the eNB2.
The inventors notice that, according to the current stop procedure, since all cells measurements which have been started previously and are ongoing should be stopped when the Registration Request IE is set to “stop”, any value included in the Cell to Report Item IE and/or Cell to Report IE will be ignored. As a result, the information, especially the cell list included in the Cell To Report IE, cannot be used to specify a “stop” action only targeting certain cells and information types of the measurements.
Therefore, it is desired to provide an efficient approach for sufficiently utilizing specific IEs in the request message, in order to stop selected measurement reports for specific cells, which have been started previously and are ongoing, according to the actual requirements of the requesting eNB.